One of the major players in innate immune system is neutrophil which is the most abundant cell type among circulating white blood cells and constitutes the first line of host defense against invading bacteria and other pathogens. The long-term objective of our research is to elucidate the molecular mechanisms and cellular signaling pathways that control various neutrophil functions. The ultimate goal is to control the number and function of neutrophils during infection and inflammation. Currently, we are particularly interested in signaling pathways mediated by inositol phospholipid PtdIns(3,4,5)P3, inositol phosphates (e.g. InsP4), and reactive oxygen species (ROS). We utilize a wide variety of approaches ranging from basic molecular and cell biology methods to high throughput chemical genetic screening and animal inflammation models to dissect these pathways.